1. Field of the Invention
The present invention relates to a data storage system, and more particularly to file storage destination volume selection control that is exercised when files used by a number of business applications are to be stored on volumes in a NAS (Network Attached Storage) system or other file system for distributively storing data on a plurality of volumes.
2. Description of Related Art
It is demanded that storage volumes offer an increased storage capacity in order to handle an increasing amount of data. Further, the important factors for storage devices are reliability characteristics and performance characteristics. The reliability characteristics are determined according, for instance, to the frequency of device failure and the capability for protecting stored data from damage in the event of a failure. The performance characteristics affect the read/write speed for the stored data or the data to be stored. It can be said that these characteristics determine the properties of storage volumes.
Meanwhile, the data to be stored on storage volumes occasionally vary in properties. It is therefore important that a storage volume having optimum reliability characteristics and performance characteristics be selected in accordance with the requirements for the data to be stored. For example, customer data and other mission-critical data should be stored on a highly fault-tolerant volume such as a RAID5 or RAID1 type. Video data, on the other hand, should be stored on a high-speed sequential access volume for effectiveness enhancement purposes.
In the following description, the expression “data storage destination optimization” is used to indicate the act of storing data on a storage volume having optimum reliability characteristics and performance characteristics in accordance with the requirements for the data to be stored.
Conventional data storage destination optimization was basically achieved by an administrator who manually managed the reliability characteristics, performance characteristics, and mount point directory of each volume.
Some large-size disk devices and virtualization products developed in recent years have a data migration function. This function works so that data previously allocated to a certain volume can be later moved to another volume, which differs in reliability characteristics and performance characteristics from the first one. Typical examples of this functionality are the data migration function of a storage subsystem product manufactured by Hitachi, Ltd. and the data migration function of a virtualization product manufactured by Data Core Software Corporation in the U.S.